1. Field of the Invention
The present invention relates to heat sink assemblies, and particularly to a heat sink assembly having a fan fixing device for attaching a fan to a heat sink and improving heat dissipating airflow.
2. Related Art
Developments in today""s highly information-intensive society have led to remarkable improvements in performances of electronic devices. During operation of many contemporary electronic devices such as central processing units (CPUs), large amounts of heat are produced. Such heat must be quickly removed from the electronic device, to prevent the system from becoming unstable or being damaged. Typically, a heat sink together with a fan is attached to an outer surface of the device to facilitate removal of heat therefrom.
Examples of conventional heat sink assemblies are disclosed in Taiwan Patent Applications Nos. 86204117, 87217628 and 86220693. Oftentimes, a fixing device for attaching a fan to a heat sink comprises a base, and a plurality of locking means for accommodating and locking the fan onto the heat sink. A circular opening is defined in a center of the base, for providing airflow access for the fan. However, a heat-generating electronic device is generally located under a center of a base of the heat sink, and the fan is a rotary fan disposed over a center of the heat sink. A temperature of the heat sink is highest at its center, yet airflow from the fan is concentrated around peripheral regions of the heat sink. The airflow does not efficiently remove heat from the center of the heat sink, the very region where heat removal is most needed.
An improved means of securing a fan to a heat sink which overcomes the above-mentioned problems is desired.
Accordingly, an object of the present invention is to provide a heat sink assembly having a fan fixing device which can improve heat dissipating efficiency.
Another object of the present invention is to provide a heat sink assembly having a fan fixing device which firmly and reliably attaches a fan to a heat sink.
To achieve the above-mentioned objects, a heat sink assembly of the present invention comprises a heat sink, a fan fixing device, and a fan. The heat sink has a base, and a plurality of fins extending from the base. Two threaded holes are defined in each of opposite sides of the base. The fan fixing device has a frame, and four legs respectively depending from four corners of the frame. A plurality of concentric guiding vanes is formed on the frame. The guiding vanes have slanted surfaces for guiding airflow toward a central portion of the heat sink. An aperture is defined in an end of each leg. A first screw extends through each aperture and engages in a corresponding threaded hole of the heat sink. The fan is attached to the frame with a plurality of second screws.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention with the attached drawings, in which: